Box lock pivot and method of assembling same



Dec. 15, 1942. F. u, GUBl. K l 2,305,156

BOX LOCK PIVOT AND METHOD OFASSEMBLING SAME Filed April 17,1941 l IIAINVENTQR Helm/Kd, 620,554

. Burku ATToRNEY Patented Dec. 15, 1942 BOX LOCK PIVOT AND METHOD OFASSEMBLING SAME Frank J. Grubel, Glendale, Long Island, N. Y., as-

signor to Edward Weck tr Company, .-Inc., Brooklyn, N. Y., a corporationof New York Application April 17, 1941, serial No. 388,972

8 Claims.

This invention relates to an improved box lock pivot for surgicalforceps or the like and the method of assembling the pivot pin with thebox lock.

Box locks for forceps or the like are old and well known and it has beenthe usual practice to use a rivet or the like as the pivot. One side orlever of the forceps was provided with a box like intermediate sectionformed by milling a rectanglar slot through the side or lever and theother side or lever was provided with a bar like section machined to tthe slot in the box and at the end of this bar like section werediagonal shoulders which cooperated with diagonal end portions of thebox. These levers were assembled by heating the box and spreading itopen far enough to receive the jaw and bar section of the other lever.The box was again heated and then the'levers were assembled and closedandthe sides of the box hammered against the sides of the bar. The barand box were drilled with a through-opening to receive a pivot pin whichwas riveted in position which in a number of instances caused the sidesof the box to be drawn up too tightly against the sides of the barmaking it necessary to provide for the proper clearance between the barand the sides of the box by opening and closing the levers afterinjecting oil and nely ground emery into the box lock joint. ends of thepivot pin and grind down the ends flush with the adjacent parts of thelevers. In these constructions the area of the outer surface of thelevers occupied by the pivot pin could not be used for the purpose of.receiving trademark or patent markings.

Among the objects of my invention is an improved box lock pivotconstruction in which the pivot pin is seated-in recesses in the innerfaces of the sides of the box and is entirely concealed by the, sides ofthe box thereby obviating the necessity of finishing operations abovereferred to and providing for a continuous surface for the reception oftrade-mark or patent markings.

Another object of the invention is the provi- Other objects of theinvention will appear from the following description taken in connectionwith thedrawing, in which- Fig. l isa disassembled View of the sides orlevers and pivot pin used in my improved method e l of construction;

It was also necessary to cut off the Fig. 2 shows the sides or leverspin of the forceps assembled;

Fig. 3 is a section on the line 3 3 of Fig. 2, showing the relation ofthe pivot pin to the elements of the box lock; Y

Fig. 4 is a top plan view of the forceps embodying my invention; and

Fig. 5fis a transverse section on the line 5-5 of Fig. 4. Y

My invention has been shown in connection with `a haernostatic forcepsof well known construction in which the side or lever I0 is providedwith the usual box lock section II, and in which the other side or leverI3 is provided with an intermediate Vbar like section I4 adjacent theend of which are diagonal shouldersV I5 and IB cooperating with diagonalshoulders I'I and I8 on the ends of the boxr of the first mentioned sideor lever. The sides or levers are provided with jaws I9 and 20 and withring handles 2l and 22 provided with cooperating catch elements 23 and24. In the usual construction the sides of the box and the bar aredrilled to receive a pivot pin which is secured in position by upsettingthe ends of the pin. It has been the practice toopen the box far enoughto receive the jawof lthe lever in which the cooperating bar is formedand to assemble the same and close them as indicated in Fig. 4, fromwhich it will appear thaty the engagement between the jaws causes theshoulders to be brought and pressed into engagement as the handles arelatched. Just before these levers were so assembled and closed and thepivot the box was heated and after the assembly the sides of the boxwere closed against the bar.

`The box and bar were then drilled to receive the -In order to avoid thevarious objections mentioned, I employ a pivot pin 25 which is of less Ylength than the combined thickness of the sides of the box and the barand preferably of hard material, and provide the lever provided with thebar with a pivot pin receiving hole of a size to provide for a close fltof the pivot pin in order that the same'may be assembled as shown inFig. 3 with its lower end preferably flush with the lower face of thebar of the box joint. In the preferred method of assembly the pivot pinmakesY its own seats in the sides of the box as the box is closed'against the sides of the bar.

In the course of experiment ball pins and pins with spherical ends wereused but it was found that these pins when the box was closed by ahammer blow on the upper side ofthe box were driven in certain instancesentirely through the bar and into the lower side of the box and it wasfound most diicult to control the nal position of the pivot pin withrespect to the sides of the box. It was also found that when both endsof the pin were round that the levers or sides of the forceps could bewabbled, thus providing `an l unsatisfactory construction. For thepurpose of preventing the possibility of wabbling the sides or leverswith respect to each other and also for the purpose of locating thepivot pin in the proper relation with respect to the elements of the boxlock joint, I employ Va pivot pin with an upper spherical end inreference to its position when the sides of the box are closed on thebar, as indicated at 39 and with a right angular lower end as indicatedat 3|. o

In the preferred method the inner faces of the sides of the boxareplain. At the time of assembling the levers the box is again heated tosoften the metal and the levers are assembled as shown in Figs. 2 and 3before the metal of the box has had a chance to cool and then as thesides of the box are closed against the bar as indicated in Figs. 4 and5 the ends of the pin make their own seats in the plain inner faces ofthe heat nitely control the amount of projection of the rounded end ofthe pivot pin from the upper side of the bar and the depth of the seatin the upper side of the box made by this end of the pivot pin.

In the operation of closing the sides of the box upon the bar, they`have been brought into a proper working contact with the bar andeasingup operations are not required. Because of the parallel engagementbetween the lower end of the pivot pin and the lower side of the box andalso because of the fact that this end seats in a shallow recess in thelower side of the box relative wabbling of the sides or levers isprevented substantially as eifectively as if both ends of the pivot pinwere right angular. Pivot pins having both ends rounded or right angularcould be used but I prefer to use pivot pins having one end rounded orat least of reduced diameter and the other end right angular to controlthe position of the pin. The construction is such that either lever maymove on the pivot, but it is obvious that the ends or intermediateportions of the pivot pin could be of rectangular or other non-circularcross section to hold the pivot pin from rotation in either lever. Thefinal position of the pivot pin might be controlled or predetermined inother ways or by other means but I prefer to control its position by theshape of its lower end as this appears to me now to be the simplest way.

While I have shown and described a preferred form of my invention asapplied to forceps and with great particularity, it is to be understoodthat I reserve the right to all such uses and changes in method and inconstruction as fall within the principles of the invention disclosedand the scope of the appended claims. v

I claim:

1. The method of assembling a pivot pin with .a box lock of pivotedlevers in which the sides of the box have inner plain faces, whichconsists in assembling a pivot pin of less length than the thickness ofthe box with the inner element of the box lock, spreading the sides ofthe box, heating the box to soften the metal, passing the lever providedwith the inner element into the box to position the pivot pin within thebox and in closing the sides of the box against the inner element andembedding the ends of the pivot pin therein while the metal of the boxis still soft.

2. The method of pivotally connecting the elements of a box lock ofpivoted levers which consists in providing a pivot pin of less lengththan the height of the box, assembling the pivot pin with the innerelement of the box lock, spreading the sides of the box, heating the boxto soften the metal, passing the lever provided with the inner elementinto the box to position the pivot pin within the box and in closing thesides of the box While the metal of the box is still soft against theinner element.

3. rThe method of pivotally connecting the elements of a box lock ofpivoted levers which consists in providing the inner element of the boxlock with a pivot pin hole, providing a pivot pin of less length thanthe height of the box with a rounded end and a `right angular end and ofa diameter to tightly fit in the pivot pin hole, inserting the pivot pininto the hole with its right angular end ush with one face of the innerelement, spreading the sides of the box, heating the box to soften themetal, passing the lever provided with the inner element and the pivotpin into the box to position the pivot pin within the box and closingthe sides of the box while the metal is still soft against the innerelement.

4. The method of assembling a pivot pin with the box lock of pivotedlevers which consists in spreading the sides of the box of the one leverto receive the other lever, providing the inner element of the box lockwith a pivot pin hole, providing a pivot pin having ends of diierentcross sectional areas and of a diameter to frictionally fit in saidhole, inserting the pivot pin in said hole, heating the box to softenthe metal, assembling said levers by passing the lever provided with theinner element into said box to position the pivot pin inside of said boxand closing the sides of said box against the inner element while themetal of the box is still soft.

5. In a box lock pivot construction, the combination with the interttingbox and inner element of the pivot construction, the inner face of oneof the sides of the box being provided with a recess, of a pivot pinassociated with the inner element and seated in said recess in the innerface of a side of the box.

6. In a -box lock pivot construction, the combination with theinteriitting box and inner element of the pivot construction, the innerface of one of the sides of the box being provided with a recess, of apivot pin extending through the inner velement of the pivot constructionand having one of its ends seated in said recess in said side of the boxof the pivot construction and having its other end seated against theinner face of the other side ofthe box of the pivot construction.

7. In a box lock pivot construction, the combination with theinterfitting box and inner element of the pivot construction, the innerfaces of both sides of said box being provided with recesses alinedtransversely of said box, of va pivot pin extending through the innerelement of the pivot construction and having its ends inner element ofthe pivot construction and having a, rounded endseated in said recessand a right angular end seated on the inner face of the other side ofthe box of the pivot construction.

FRANK J. GRUBEL.

